Good luck with this sh!t - I once wasted 100 EUR on a similar poor design that zapped several EPROMs (and collectible 8751's in cerdip package with gold lid), even with running the DOS software on a 486 peecee to avoid *lose*dows. I will never rely on latches hooked to a parallel port to control critical signals like Vpp without any self-test or at least some software test routines with test points on the board to check with oscilloscope. It was eventually honest enough to destroy itself and burned a few transistors onboard. There may be serious programmers on good old parallel port made by Data I/O, but US or EU brands are too expensive for hobbyists... so bought a chinese one: Wellon VP-480. It has a self-test, a serious wall wart power supply, supports many devices, and can test usual logic gates. One year later, it's well worth the expense if used more than once a month.